"We won't get a full figure until building impact assessment teams on the ground have been able to conduct reports," Mr Allan said.

Mr Allan said 194 firefighters, 50 vehicles and at least 10 aircraft were working to establish containment lines on Friday but struggled in the face of 34-degree heat and winds of more than 30 kilometres an hour.

Firefighters respond to a fire at Carwoola, southeast of Canberra on Friday. Photo: Alex Ellinghausen

He said crews would remain on the ground overnight and try to control the fire before facing potentially worse conditions on Saturday.

"If it is not contained by tomorrow, higher temperatures will make it harder for firefighters to bring it under containment."

Firefighters told residents near Carwoola and Captains Flat it was too late to leave at about 3pm on Friday.

Those in the area of Hoskinstown, Rossi, Forbes Creek and Primrose Valley were urged to seek shelter, with properties under threat along Widgiewa Road, Whiskers Creek Road, Yilgarn Road and Captains Flat Road.

Two evacuation centres were set up at Bungendore Public School hall and the Q Theatre in Queanbeyan, where school children travelling on buses were also redirected.

Captains Flat Road remained closed between Briars Sharrow Road and the Kings Highway on Friday.

A total fire ban was enforced in the ACT and surrounding NSW region on Friday.

Pip Wyrdeman observes the fire where her dad's home is, during a fire at Carwoola, southeast of Canberra. Photo: Alex Ellinghausen

A spokesman for the ESA said the fire, which was travelling in an eastbound direction, did not pose any threat to the ACT.

NSW fire crews were also battling a fire in Blayney, west of Bathurst, on Friday afternoon.